20
24
Human chorionic gonadotropin (
hCG
) from embryo maintains corpus luteum.
P
and
E
from CL sustain the endometrium.
Pregnancy
Receptive
hCG
P
E
Langman’s Medical Embryology, 8th ed., TW Sadler Lippincott, Williams & Wilkins (Philadelphia) 2000, p. 45 (revised)
The prepared endometrium
hCG detected in mother’s urine at least by 8 days.
